European Forests Could ‘Live Fast and Die Young’ in a Warming Climate

Climate change could cause trees to grow faster, accelerating the rate at which they absorb carbon from the atmosphere. But these trees may be likely to die sooner, a study finds.The research, conducted in high-altitude conifer forests in Spain and Russia, suggests that climate change could cause the trees to “live fast and die young”, the authors say – reducing the ability of these forests to act as a carbon sink over long timescales.The findings show that planting forests to soak up greenhouse gas emissions could have more limited potential than previously thought, the lead author tells Carbon Brief.The research is “impressive”, but may be too “bold” in its conclusions, another scientist tells Carbon Brief.Going greenWhen humans release CO2 into the atmosphere, around one quarter of it is absorbed by plants.Plants use CO2 during photosynthesis to create new materials, such as leaves, shoots and roots. Because of this, forests act as “carbon sinks” – storing vast amounts of carbon over long timescales.Climate change is likely to increase the rate at which trees grow. The study focuses on one reason for this, which is that warming temperatures may increase the overall length of the growing season in temperate regions, explains Prof Ulf Büntgen, a researcher of environmental systems analysis from the University of Cambridge and lead author of the study published in Nature Communications. He tells Carbon Brief:

“The common belief is that in a warmer and a more CO2-enriched world, trees will uptake more carbon from the atmosphere. Based on this, people are starting political actions to plant trees. What we are adding to this debate, is to say: ‘This is correct but it’s only half of the story.’“What is neglected is the ‘carbon residence time’ – how long the carbon taken up by terrestrial vegetation is actually captured. In our study, we show that faster growing trees and other types of vegetation will die younger. By doing that, they are going to release all of the carbon that they have sequestered.”